I just obtained an older api 525C compressor (s/n 2268,
Huntington, NY).

I installed it in my 6B lunchbox, but it's not passing
signal. Maybe the unit needs to be serviced, but I first
wanted to find out if the older units had different pin
configurations than the current issue.

I've seen an undated 525 document that did in fact have
a different pinout scheme than the current line of
modules. Does anyone know if and when they changed this?

I tried calling api, but the head tech is off at the NAB
show and the person I spoke to didn't know the answer.

Many thanks.
--
--
John Noll
Retromedia Sound Studios
Red Bank, NJ



http://www.retromedia.net

Original 525 compressors are wired difft. than the eqs. The pinout is
in revearse of the eqs if I recall correctly. At any rate you'll need
to rewire the comp. for it to work in a standard rack or lunchbox.

I don't think the wiring changed until the reincarnated API began
building new 525 comps in the 1990's (?) I am fairly certain that any
525 w/ the analog meter will have been built with the old opposite
pinout.

Good luck.

Mark Linett


John Noll wrote:
I just obtained an older api 525C compressor (s/n 2268,
Huntington, NY).

I installed it in my 6B lunchbox, but it's not passing
signal. Maybe the unit needs to be serviced, but I first
wanted to find out if the older units had different pin
configurations than the current issue.

I've seen an undated 525 document that did in fact have
a different pinout scheme than the current line of
modules. Does anyone know if and when they changed this?

I tried calling api, but the head tech is off at the NAB
show and the person I spoke to didn't know the answer.

Many thanks.
--
--
John Noll
Retromedia Sound Studios
Red Bank, NJ



http://www.retromedia.net

yrplace wrote:
Original 525 compressors are wired difft. than the eqs. The pinout is
in revearse of the eqs if I recall correctly. At any rate you'll need
to rewire the comp. for it to work in a standard rack or lunchbox.

I don't think the wiring changed until the reincarnated API began
building new 525 comps in the 1990's (?) I am fairly certain that any
525 w/ the analog meter will have been built with the old opposite
pinout.

Good luck.

Mark Linett


I have figured it out and modified the 525 by cutting
some of the traces and wiring some jumpers. It's now up
and running. The way to tell if it's the old
configuration is if the meter lamp has it's own pair of
pins (10 & 11) for 24V. The newer versions derive meter
bulb power directly from 16V.

Brad Avenson was kind enough to post a document he had
that explains the pinout differences:

http://avensonaudio.com/tech/API/API...t%20change.JPG

There's also some helpful docs on Dan Alexander's website.
--
--
John Noll
Retromedia Sound Studios
Red Bank, NJ


http://www.retromedia.net